Example

Notes

When called on an HTML element in a DOM flagged as an HTML document, getAttribute() lower-cases its argument before proceeding.

Essentially all web browsers (Firefox, Internet Explorer, recent versions of Opera, Safari, Konqueror, and iCab, as a non-exhaustive list) return null when the specified attribute does not exist on the specified element and this is what the current DOM specification draft specifies. The old DOM 3 Core specification, on the other hand, says that the correct return value in this case is actually the empty string, and some DOM implementations implement this behavior. The implementation of getAttribute in XUL (Gecko) actually follows the DOM 3 Core specification and returns an empty string. Consequently, you should use element.hasAttribute() to check for an attribute's existence prior to calling getAttribute() if it is possible that the requested attribute does not exist on the specified element.